A numerical simulation on recirculation phenomena of the plume generated by obstacles around a row of cooling towers

Lee, J.H.; Moshfeghi, Mohammad; Choi, Y.; Hur, Nahmkeon

doi:10.1016/j.applthermaleng.2014.04.021

Cited by 13 publications

(6 citation statements)

References 6 publications

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“…Re-entry of hot air back into the tower were reported for mechanical cooling towers [18][19][20]. This strange airflow behaviour is usually due to the limited space around the cooling tower.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Gurgenci

Guan

et al. 2018

Applied Thermal Engineering

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Section: Introductionmentioning

confidence: 99%

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Gurgenci

Guan

et al. 2018

Applied Thermal Engineering

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“…MCTs are widely used as one of the most economical, efficient, and energy-efficient ways to remove heat. Theoretical studies on the performance of cooling towers began in the 1970s [4]. To better serve cooling tower buyers and designers, the Cooling Technology Institute (CTI) of the USA issued a series of specifications and standards.…”

Section: Introductionmentioning

confidence: 99%

“…J.H. Lee et al [4] studied the HAR and plume generation of a row of cooling towers with obstacles around them, but most of the research focused on water content. The presence of obstacles affects the temperature and humidity of the air at the air inlet of the cooling towers.…”

Section: Introductionmentioning

confidence: 99%

“…There is a lot of literature on the use of computational fluid dynamics (CFD) technology to study the effect of windbreak walls on the thermal performance of cooling towers [17,[23][24][25]. Lee et al [4] conducted a three-dimensional parametric study of the gap between the cooling tower entrance area and the obstacle. Fan and Dong [26] studied the effect of MCTs on the cooling performance of air-cooled condensers in complex environments.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of the Hot Air Recirculation Effect and Relevant Empirical Formulae Applicability for Mechanical Draft Wet Cooling Towers

et al. 2020

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Due to the hot air recirculation, the inlet air enthalpy h1 of mechanical draft wet cooling towers (MCTs) was usually greater than the ambient air enthalpy ha. To realize the cooling performance and accurate design of MCTs, this paper clarified the feasibility of the inlet air enthalpy empirical formula presented by the Cooling Technology Institute (CTI) of the USA. A three-dimensional (3D) numerical model was established for a representative power plant, with full consideration of MCTs and adjacent main workshops, which were validated by design data and published test results. By numerical simulation, the influence of different wind directions and wind speeds on hot air recirculation (HAR) and the influence of HAR on the cooling performance of the MCTs were qualitatively studied based on the concept of hot air recirculation rate (HRR), and the correction value of HRR was compared with the calculated value of the CTI standard. The evaluation coefficient ηh, representing the ratio of the corrected value to the calculated value was introduced to evaluate the applicability of the CTI formula. It was found that HAR was more sensitive to ambient crosswind, and an increase in HRR would deteriorate the tower cooling performance. When the crosswind speed increased from 0 to 15 m/s, ηh, changed from 2.42 to 80.18, and the calculation error increased accordingly. It can be concluded that the CTI empirical HRR formula should be corrected when there are large buildings around the MCTs, especially under high-speed ambient crosswind conditions.

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“…Re-entry of hot air back into the tower were reported for mechanical cooling towers [167][168][169]. This strange airflow behaviour is usually due to the limited space around the cooling tower.…”

mentioning

confidence: 99%

Numerical and experimental study of small natural draft dry cooling tower for concentrating solar thermal power plant

Li¹

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The typically arid climates in the likely locations for renewable thermal power plants such as Concentrating Solar Thermal (CST) power plants provide the motivation for dry cooling technology applications. Natural draft dry cooling tower (NDDCT) with low maintenance cost and no parasitic power consumption offers a feasible and cost effective option for such applications. Compared with the conventional coal fired and nuclear power plants, the size of the CST power plant proposed for Australian regional communities is much smaller. However, the existing cooling tower design is optimised for large steam power plants, and is not optimal for these renewable power plants. (2) The performance of the experimental tower was tested at two constant heat loads of 600 kW and 840 kW, respectively, with various ambient temperatures. The 1D numerical model was refined and validated with the experimental data. The thermodynamic model of a 1 MW CST power plant running with sCO2 cycle was developed and integrated with the updated cooling tower model. Significant differences were observed between the steam Rankine and sCO2 cycles in terms of the effect of the ambient temperature on power generation. The differences between steam Rankine and sCO2 Brayton cycle in this context were analysed and discussed.(3) Two potential cooling issues with small NDDCT, the crosswind and the cold inflow, were identified and the detail experimental data were presented. The crosswind effect on small cooling tower is different from the conventional big cooling towers. With the increase of the crosswind speed, the overall cooling performance of the small NDDCT first decreases and then increases. The mixed convection theory and the Richardson Number were proposed to explain this phenomenon. On the other hand, repeated cold inflow events were observed during the tests, which cause a significant decrease of the air temperature inside the cooling tower. The water outlet temperature can be increased up to 3°C as a result of the cold inflow effect. Further analysis of the mechanism shows that the cold air incursion at the top of the cooling tower could decrease the driving force and also form an extra flow resistance for the airflow through the heat exchanger.(4) Based on the working mechanism of the air-cooled heat exchanger and the crosswind effect on NDDCT, this study proposed a new method to increase the cooling performance of NDDCT under crosswind conditions by optimizing the water mass flow rate in the air-cooled heat exchangers. By optimising the water distribution, the water outlet temperature of each heat exchanger is more uniform and the adversely influence of the crosswind can be effectively relieved.The findings in this paper can lay an important foundation for future small cooling tower design and operation.

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A numerical simulation on recirculation phenomena of the plume generated by obstacles around a row of cooling towers

Cited by 13 publications

References 6 publications

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Experimental study of cold inflow effect on a small natural draft dry cooling tower

Evaluation of the Hot Air Recirculation Effect and Relevant Empirical Formulae Applicability for Mechanical Draft Wet Cooling Towers

Numerical and experimental study of small natural draft dry cooling tower for concentrating solar thermal power plant

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